CVE-2026-49216 Symfony UX: XSS in symfony/ux-autocomplete via unescaped AJAX response data
An attacker can execute arbitrary JavaScript in a victim's browser via unescaped AJAX response data in the Symfony UX autocomplete component.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-49216?
CVE-2026-49216 is a medium-severity cross-site scripting vulnerability in symfony ux, published on 17 Jul 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
Symfony UX is a JavaScript ecosystem for Symfony. From 2.2.0 until 2.36.0 and 3.1.0, the Stimulus controller in symfony/ux-autocomplete renders AJAX response items in _createAutocompleteWithRemoteData() by interpolating the text field into HTML template literals (<div>${item[labelField]}</div>) rather than text, allowing attacker-controlled markup from user-supplied dropdown values to execute in the browser of any user who opens an autocomplete widget backed by the same data. This issue is fixed in versions 2.36.0 and 3.1.0.
Weakness: CWE-79
Which versions are affected by CVE-2026-49216?
4 open source packages ship an affected version, including symfony/ux-autocomplete. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
symfony/ux-autocomplete Packagist | From 2.2.0 | 2.36.0 |
symfony/ux-autocomplete Packagist | From 2.2.0 | 2.36.0 |
symfony/ux-autocomplete Packagist | From 3.0.0 | 3.1.0 |
symfony/ux-autocomplete Packagist | From 3.0.0 | 3.1.0 |
Products include Symfony Ux.
How do I fix CVE-2026-49216?
Upgrade symfony/ux-autocomplete to a fixed version for your release line: 2.36.0 or 3.1.0.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-49216 being exploited?
There is no known exploitation of CVE-2026-49216 in the wild and no public exploit code.
Other vulnerabilities in symfony ux
- CVE-2026-49208 Symfony UX: Format-less date LiveProps parsed with the permissive DateTime constructor
- CVE-2026-49211 Symfony UX: Information exposure via unescaped LIKE wildcards in EntitySearchUtil
- CVE-2026-49212 Symfony UX: LiveComponentHydrator HMAC checksum lacks component and slot binding
- CVE-2026-55877 Symfony UX: XSS in symfony/ux-icons via unsanitized SVG content in local files and Iconify on-demand responses
- CVE-2026-49209 Symfony UX: Denial of service in symfony/ux-live-component via unbounded batch action requests
Sources
Also known as GHSA-mwqm-4fw3-cjvr.